The present invention generally relates to the field of steerable catheters. More specifically, the invention is directed to a steerable catheter which includes a single pull wire arranged to allow the catheter to achieve various complex curvatures.
Catheters are used for an ever-growing number of procedures. For example, catheters are used for diagnostic, therapeutic, and ablative procedures, to name just a few examples. Typically, the catheter is manipulated through the patient""s vasculature and to the intended site, for example, a site within the patient""s heart. The catheter typically carries one or more electrodes, which may be used for ablation, diagnosis, or the like.
In order to manipulate the catheter through a patient""s vasculature, the catheter must be flexible. In addition, such catheters are preferably steerable, so that the clinician may impart a desired curve to the catheter from a remote location in order to pass through curved areas within a patient. A conventional steerable catheter includes a pull wire which extends through the catheter shaft, and connects to the catheter adjacent the distal end of the catheter at an off-axis location. The pull wire connects to a control knob, slide actuator, or other suitable manipulating member that is mounted in a control handle. A form of such a catheter is disclosed in U.S. Pat. No. 5,383,852 to Stevens-Wright and assigned to the assignee of the rights in the present invention.
While such catheters have gain widespread acceptance in the industry, they nevertheless suffer from certain shortcomings. One shortcoming is that to achieve relatively complex curves, those catheters require multiple pull wires which extend through different lumen and which connect to the catheter at different anchoring points. In addition, the pull wires each require a separate manipulating member to tension the respective pull wires. Thus, in a conventional steerable catheter, a relatively large amount of space is occupied by the steering subsystem, which limits the amount of space available for other components.
In addition, ablation catheters typically must assume various curves so that the ablation electrodes carried on the catheter will come into contact with a patient""s tissue at selected locations. Thus, for that additional reason, catheters should be able to assume complex curves.
Accordingly, it will be apparent that there continues to be a need for a steerable catheter which can achieve relatively complex curves to facilitate manipulation of the catheter through a patient""s vasculature and to an intended site. Moreover, the needs exists for such a catheter with a steering subsystem that occupies a relatively small amount of space within the catheter. The instant invention addresses these needs.
Briefly, the present invention is in the form of a catheter that includes a pull wire which extends through two different lumen and attaches to the distal end of the catheter. By tensioning the pull wire, the catheter can assume various complex curves, depending on the different lumen through which the pull wire passes. A proximal segment of the catheter can assume a curve in a first plane, while a distal segment of the catheter can assume a curve in a different plane, thereby achieving a three-dimensional curvature with a single pull wire.
Thus, according to one illustrative embodiment, the present invention is directed to a medical device including an elongated shaft, the shaft being formed with a first lumen extending at least partway through the shaft, and a second lumen extending at least partway through the shaft, the first and second lumen being offset by a predetermined angular distance, the shaft being further formed with a transition region defining a passage leading from the first lumen to the second lumen; a single pull wire extending through the first lumen, the passage in the transition region, and the second lumen; and means for actuating the pull wire to impart a desired curve to the shaft.
In another illustrative embodiment, the invention is directed to a medical device that includes a handle including a pull wire tensioning member, the pull wire tensioning member being manipulable relative to the handle; an elongated shaft connected to the handle, the shaft being formed with a first lumen extending at least partway through the shaft, and a second lumen extending at least partway through the shaft, the first and second lumen being offset by a predetermined angular distance, the shaft being further formed with a transition region defining a passage leading from the first lumen to the second lumen; and a pull wire connected to the tensioning member and extending through the first lumen, the passage in the transition region, and the second lumen.